com.google.gitiles.BaseServlet.java Source code

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Here is the source code for com.google.gitiles.BaseServlet.java

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// Copyright 2012 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.google.gitiles;

import static javax.servlet.http.HttpServletResponse.SC_NOT_FOUND;

import com.google.common.base.Charsets;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import com.google.common.net.HttpHeaders;

import org.joda.time.Instant;

import java.io.IOException;
import java.util.Map;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/** Base servlet class for Gitiles servlets that serve Soy templates. */
public abstract class BaseServlet extends HttpServlet {
    private static final String DATA_ATTRIBUTE = BaseServlet.class.getName() + "/Data";

    static void setNotCacheable(HttpServletResponse res) {
        res.setHeader(HttpHeaders.CACHE_CONTROL, "no-cache, no-store, max-age=0, must-revalidate");
        res.setHeader(HttpHeaders.PRAGMA, "no-cache");
        res.setHeader(HttpHeaders.EXPIRES, "Fri, 01 Jan 1990 00:00:00 GMT");
        res.setDateHeader(HttpHeaders.DATE, new Instant().getMillis());
    }

    public static BaseServlet notFoundServlet() {
        return new BaseServlet(null) {
            @Override
            public void service(HttpServletRequest req, HttpServletResponse res) {
                res.setStatus(SC_NOT_FOUND);
            }
        };
    }

    public static Map<String, String> menuEntry(String text, String url) {
        if (url != null) {
            return ImmutableMap.of("text", text, "url", url);
        } else {
            return ImmutableMap.of("text", text);
        }
    }

    protected static Map<String, Object> getData(HttpServletRequest req) {
        @SuppressWarnings("unchecked")
        Map<String, Object> data = (Map<String, Object>) req.getAttribute(DATA_ATTRIBUTE);
        if (data == null) {
            data = Maps.newHashMap();
            req.setAttribute(DATA_ATTRIBUTE, data);
        }
        return data;
    }

    protected final Renderer renderer;

    protected BaseServlet(Renderer renderer) {
        this.renderer = renderer;
    }

    /**
     * Put a value into a request's Soy data map.
     * <p>
     * This method is intended to support a composition pattern whereby a
     * {@link BaseServlet} is wrapped in a different {@link HttpServlet} that can
     * update its data map.
     *
     * @param req in-progress request.
     * @param key key.
     * @param value Soy data value.
     */
    public void put(HttpServletRequest req, String key, Object value) {
        getData(req).put(key, value);
    }

    protected void render(HttpServletRequest req, HttpServletResponse res, String templateName,
            Map<String, ?> soyData) throws IOException {
        try {
            res.setContentType(FormatType.HTML.getMimeType());
            res.setCharacterEncoding(Charsets.UTF_8.name());
            setCacheHeaders(req, res);

            Map<String, Object> allData = getData(req);
            allData.putAll(soyData);
            GitilesView view = ViewFilter.getView(req);
            if (!allData.containsKey("repositoryName") && view.getRepositoryName() != null) {
                allData.put("repositoryName", view.getRepositoryName());
            }
            if (!allData.containsKey("breadcrumbs")) {
                allData.put("breadcrumbs", view.getBreadcrumbs());
            }

            res.setStatus(HttpServletResponse.SC_OK);
            renderer.render(res, templateName, allData);
        } finally {
            req.removeAttribute(DATA_ATTRIBUTE);
        }
    }

    protected void setCacheHeaders(HttpServletRequest req, HttpServletResponse res) {
        setNotCacheable(res);
    }
}